oral histo enamel

• Enamel is a substance known as Substantia adamantia or Ectodermal derivative that covers the entire anatomical crown of tooth and provides contour and shape to the crown.
• The course or direction of enamel rods is an important consideration in cavity preparation.
• Enamel is brittle and must be supported by sound dentin.
• Presence of deep pits and fissures predispose teeth to dental caries.
• Dental lamellae and enamel tufts are predisposing location for dental caries.
• Enamel is permeable to fluoride and other substances.
• Keep the cervical surface of enamel well polished and smooth.
• The process of etching produces pitting and irregularities that aids in microretention of the restoration.
• Enamel cuticle is a delicate membrane that covers the entire crown of newly erupted tooth and is derived from the ameloblast.
• Enamel rods, also known as enamel prisms, may vary from 5-12m in number and have three parts: the body or head, the neck and the tail.
• Enamel rods follow a wavy course from DEJ to surface of enamel and in cross section may appear as fish scale, paddle shaped or may have a keyhole pattern.
• Enamel tufts appear as tufts of grass that project into the enamel and are narrow ribbonlike structures.
• Enamel lamellae are thin, leaflike structures that extend from enamel surface towards DEJ and even towards dentin and are organic in nature and hypomineralized.
• Gnarled enamel is characterized by the intertwining or twisting of enamel rods at incisal or cuspal region and aids in resisting high masticatory loads without fracture.
• Enamel pearls, also known as enamel droplets, are HERS that becomes detached and differentiate into ameloblasts and forms enamel in the bifurcation or trifurcation of teeth.
• Enamel cracks are narrow fissurelike structures which are actually outer edges of the enamel lamellae.